In 2010, in writing "Super Bugs: Survival of the Fittest,"1 I detailed the global spread of a new virulent "super bug" (SB) dubbed New Delhi metallo-[beta]-lactamase-1 (NDM-1).1 The term super bug is a colloquial reference to a bacterium that carries resistant genes to many antibiotics. The SB NDM-1 facilitates the resistance of a variety of bacteria, especially Escherichia coli, and gene transfer induces multidrug resistance (MDR).1,2
First identified in India, NDM-1 subsequently appeared in several other countries.2 Its recent epidemiologic spread is related to globalization and indiscriminate use of antibiotics.2 Of late, some refugees of the wars in the Middle East and Syria were identified as carriers of SBs. The majority of MDR strains were recovered from young men, consistent with the profile of civilians wounded in Syria and other countries.2 In many cases, these patients had no history of previous hospitalization, indicating that the circulation of MDR strains may be community acquired.2
The SB concept can be applied to any bacterium or virus of a significantly enhanced virulence. Although recent surveillance places an emphasis on bacteria resistant to available antibiotics in the medical therapeutic armamentarium, fungi are beginning to manifest drug resistance along with epidemiologic migrations similar to path of NDM-1 and other SBs.1,2
In 2009, a single strain of a novel ascomycetous yeast species belonging to Candida auris was isolated from the external ear canal of an inpatient in a Japanese hospital.3 Because the isolate was from ear canal discharge of a human patient, it was named "auris."3 The C auris species is concerning because of its reduced sensitivity to antifungal agents, specifically azoles and amphotericin B, in combination with the lack of reliable culture-based methods for its identification.3,4
More recently, C auris has been associated globally with life-threatening invasive diseases of the bloodstream and wound infections.3,4 Epidemiologically, C auris appears to be following the same global path of NDM-1. The reported affected countries include India, Japan, Kuwait, South Africa, South Korea, Spain, and the United Kingdom. Recently, 98 cases were reported in the United States.5
Biofilm formation is a prime catalyst for Candida albicans pathogenicity and its associated morbidity and mortality in susceptible patients, such as patients with diabetes and chronic wounds. In contrast to C albicans, C auris can differentially adhere to polymeric surfaces, form biofilms, and resist antifungal agents.4 Moreover, Sherry et al4 found that caspofungin was mostly inactive against C auris biofilms; this finding was unexpected because caspofungin is usually highly effective against Candida biofilms.
These qualities contribute not only to C auris virulence but also its survivability in hospital environments, increasing its capability to cause outbreaks associated with aggregative capacity, and make it an emerging pathogen. Sherry et al4 suggest "[horizontal ellipsis]it is improbable that the spread and prevalence of C auris can be controlled with standard antifungal regimens alone."
Most C auris infections were treatable with polyenes, azoles, and echinocandins; however, some C auris infections have been resistant to all 3 of these main classes of antifungal medications.4 Treatment decisions should be made in consultation with an infectious disease specialist, because multiple classes of antifungals at high doses may be required to eradicate the infection.4
Once C auris gets into a healthcare facility, it tends to stay. Hospital transmission occurs because C auris likes to stay on skin and is hard to kill when it gets on hospital surfaces and fomites.6-8 Infection prevention measures targeting C auris biofilms in patients using medical devices (eg, equipment in contact with patients) and in the hospital environment are therefore required. Promisingly, it was demonstrated that chlorhexidine is effective against C auris.4 Therefore, use of chlorhexidine disinfectant may have utility for topical control of C auris at standard concentrations used for skin and wound cleansing and disinfection (0.05%-4.0%).4
The Centers for Disease Control and Prevention provides medical surveillance intelligence6-8 on the emerging problems related to C auris. They also provide infection control recommendations for outpatient settings (eg, primary care offices and wound clinics).5-8
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